This study will test the hypothesis that patients with Barrett's esophagus (BE) have a more severe defect in esophageal function and more gastroesophageal reflux (GER) compared to patients with uncomplicated GERD without BE and normal volunteers. This will be accomplished using a recently developed technology of multichannel intraluminal impedance (MII) as a more sensitive test of esophageal function and as a means of assessing GER of all types (acid and non-acid). Incorporating a special catheter, MII combined with intraluminal pressure transducers provides a more sensitive test of esophageal function, including the ability to measure bolus transit without radiation exposure. Likewise, a special catheter in which pH sensitive electrodes are combined with MII provides a sensitive technique to identify all forms of GER, independent of pH. We will prospectively study esophageal function and characteristics of GER in 20 patients with BE, 20 patients with uncomplicated GER (patient controls) and 20 healthy volunteers (normal controls). Following a baseline assessment, all participants will be treated with a proton pump inhibitor (esomeprazole 40mg) taken twice daily for a period of 8 weeks. Upon completion of 8 weeks of intensive therapy, each patient will have repeated studies of esophageal function while continuing on the acid suppressing regimen. These studies will identify whether acid suppression is as effective in patients with BE as in those with uncomplicated GERD and normal volunteers, including assessment of the level of intragastric acidity and evidence of persistent reflux, both the acid and non-acid component. It is anticipated that the studies outlined in this proposal will provide better clarification of the esophageal functional abnormalities occurring in patients with BE that permit a more aggressive form of gastroesophageal reflux disease. [unreadable] [unreadable]